The skull is divided into two main divisions - the cranium and face. The cranium contains 8 bones that enclose and protect the brain, including the frontal, parietal, temporal, occipital, sphenoid, and ethmoid bones. The 14 facial bones form the framework of the face and contain openings for sensory organs, food/air passage, and secure the teeth. All skull bones are firmly joined together by sutures. The temporal bones form the sides of the skull and contain structures like the external ear. The sphenoid and ethmoid bones have complex shapes and articulate with many other bones. The maxillary bones make up the upper jaw.

1. THE SKULL
2 Divisions
Cranium
Face

2. • Most complex bony structure
• 22 bones in all
• Mostly flat bones.

5. Cranial Bones: 8
• 1. frontal bone
• 2. occipital bone
• 3. sphenoid bone
• 4. ethmoid bone
• 5. parietal bones (2)
• 6. temporal bones (2)

6. Functions of Cranial Bones
• Enclose and protect the brain
• Attachment sites for head and neck
muscles

7. Facial Bones: 14
• The bones of the facial skeleton(14) are
– The vomer
– Two nasal conchae,
– two nasal bones
– Two maxilla
– The mandible
– Two palatine bones
– Two zygomatic bones and
– Two lacrimal bones.

9. Functions of Facial Bones
• 1. form framework of face
• 2. contain cavities for special sense
organs
• 3. openings for food/air passage
• 4. secure the teeth
• 5. anchor the facial muscles of expression

10. • ALL BONES OF THE SKULL ARE
FIRMLY LOCKED IN PLACE BY JOINTS
CALLED SUTURES
• Four major sutures:
– Coronal suture
– Sagittal suture
– Lambdoid suture
– Squamosal or squamous suture

11. THE CRANIUM (8)
1 frontal bone
2 parietal bones
2 temporal bones
1 occipital bone
1 sphenoid bone
1 ethmoid bone

12. THE FRONTAL BONE

13. Parietal Bones: Form most of the superior
and lateral aspects of the skull
Figure 7.3a

14. Parietal Bones
• Curved, rectangular bones forming
majority of the cranium
• All four major sutures articulate with this
bone

15. Parietal Bones and Major Associated Sutures
• Four sutures mark the articulations of the
parietal bones
– Coronal suture – articulation between
parietal bones and frontal bone anteriorly
– Sagittal suture – where right and left parietal
bones meet superiorly
– Lambdoid suture – where parietal bones
meet the occipital bone posteriorly
– Squamosal or squamous suture – where
parietal and temporal bones meet

17. Occipital Bone
• Forms most of
skull’s posterior
wall and base
• Major markings
include the
posterior cranial
fossa, foramen
magnum, occipital
condyles, and the
hypoglossal canal Figure 7.2b

18. Temporal Bones
• Lateral sides of the skull
• Zygomatic process connects with
zygomatic arch
• External auditory meatus (external ear)
• Styloid process muscle attachment for
tongue and neck
• Mastoid process neck muscles

19. Temporal Bones
Figure 7.5

20. Sphenoid Bone
• Spans width of middle cranial fossa
• Articulates with all other cranial bones
• Three parts greater wing, lesser wing
and pterygoid processes
• Sella turcica enclosure for pituitary
gland

23. Ethmoid Bone
• Complex shape
• Nasal cavity and orbital cavity
• Cribriform plate roof of the nasal cavity
• Crista galli- outermost covering of the
brain cover connects here

26. Maxillary Bones
• Medially fused bones that make up the
upper jaw and the central portion of the
facial skeleton
• Facial keystone bones that articulate with
all other facial bones except the mandible
• Their major markings include palatine,
frontal, and zygomatic processes, the
alveolar margins, inferior orbital fissure,
and the maxillary sinuses

27. Maxillary Bone
Figure 7.8b